<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>

    <style>

        #a {
            width: 100px;
            height: 100px;
            background-color: antiquewhite;
        }

        #b {
            width: 100px;
            height: 100px;
            background-color: aquamarine;
        }

    </style>
</head>
<body>
<div id="a">
    <div id="content" draggable="true">Hello World</div>
</div>
<div id="b">

</div>

<script src="main.js"></script>
</body>
</html>